This invention relates to a bis-chelating ligand composition, particularly of Group VB elements (P, As, Sb), and its use in transition metal complex catalyzed reactions. Preferably, this invention relates to a bis-chelating ligand composition, particularly of Group VB elements, and its use in transition metal-ligand complex catalyzed carbonylation processes, preferably, hydroformylation processes.
Carbonylation processes directed to the production of oxygenated products are well known and generally involve reaction of an organic compound with carbon monoxide and often a third reactant, preferably, hydrogen. See, for example, J. Falbe, “New Syntheses With Carbon Monoxide,” Springer Verlag, New York, 1980. Such processes may include the carbonylation of organic compounds, such as olefins, acetylenes, alcohols, and activated chlorides, with carbon monoxide, and optionally, either hydrogen, alcohol, amine, or water, as well as ring closure reactions of functionally unsaturated compounds, for example, unsaturated amides, with carbon monoxide. One major class of known carbonylation processes comprises the hydroformylation of an olefinic compound with carbon monoxide and hydrogen to produce aldehydes, followed if desired by reduction of the aldehyde to alcohol; or reductive amination of the aldehyde to amine; or oxidation of the aldehyde to carboxylic acid; or aldolization of the aldehyde followed by oxidation to hydroxyacid. Oxygenated products, such as alcohols, carboxylic acids, and hydroxyacids find utility in a multitude of applications, including as solvents, surfactants, monomers for the preparation of polymers, and as intermediates in the synthesis of pharmaceuticals and other industrial chemicals.
Carbonylation processes are known to be facilitated by metal-ligand complex catalysts, such as Group VIII transition metal-phosphorus ligand complex catalysts. Representative art disclosing a variety of hydroformylation catalysts of various triorganophosphine, triorganophosphite, diorganophosphite, and bisphosphite ligands is found in the following references: U.S. Pat. No. 3,527,809; U.S. Pat. No. 4,599,206; U.S. Pat. No. 4,748,261; and WO-A1-02/00670. Likewise, triorganoarsine and triorganoantimony ligands are known for analogous carbonylation processes as disclosed, for example, in WO-A1-01/085739, WO-A1-01/058589, WO-A1-00/009467, U.S. Pat. No. 6,156,936, and U.S. Pat. No. 4,755,625. Disadvantageously, many of the transition metal-ligand complex catalysts disclosed for these carbonylation processes exhibit undesirably low activity or insufficient stability. More disadvantageously, many of the disclosed transition metal-ligand complex catalysts exhibit high isomerization selectivity of long chain alpha-olefins to internal olefins. Even more disadvantageously, many of the ligands disclosed in the art cannot be easily fine-tuned to provide high selectivity to the desired hydroformylation product.
In view of the above, a search continues in the art to find novel bis-chelating ligands that will provide improved activity, improved stability, improved isomerization selectivity, and/or improved ease of fine-tuning selectivity in carbonylation processes, preferably, hydroformylation processes.